A typical liquid crystal display (LCD) device employs light emitting diodes (LEDs) as a backlight source. A plurality of LED lights are connected in series to form an LED lightbar, and the LED lightbar is coupled to a boost circuit. As shown in FIG. 1, a controllable switch Q of the boost circuit is coupled to a backlight driver integrated chip (IC), an output voltage of the boost circuit is regulated by regulating a duty cycle of an output signal of a driver pin G of the backlight driver IC, to dim the LED lightbar. If a plurality of LED lightbars are used, the LED lightbars may be arranged in parallel and coupled to a same boost circuit. The backlight driver IC comprises a comparator, where an output end of each LED lightbar is coupled to an inverting input end of the comparator, and a non-inverting input end of the comparator is coupled to a reference voltage. The comparator regulates the duty cycle of the output signal of the backlight driver IC according to a voltage difference between the reference voltage and each LED lightbar, thereby dimming the LED lightbar. A typical backlight driver module may exhibit poor circuit performance, for example, when the backlight driver module is still outputting a high voltage when the LED lightbars are under a light load (brightness of LED lightbars is low), resulting in efficiency reduction of backlight driver, or when the backlight driver module still outputs low voltage when the LED lightbars are under a heavy load (brightness of LED lightbars is high), resulting in that expected brightness of the LED lightbars may not be achieved